1. Field of the Invention
The present invention relates to a processor, memory, computer system, and method of authentication.
2. Description of the Related Art
Computer is incorporated into various devices such as digital cameras, digital televisions, digital versatile disk (DVD) players, DVD/HDD recorders, game consoles, portable telephones, portable audio players, and controlling units of automotives. The devices or systems incorporating the computer handle data contents that are under copyrights protection, as well as important information such as personal information and charging information.
Illegal act using these devices or systems causes a serious problem; for example, one can illegally alter the device/system to decrypt and illegally copy the contents, run an illegal program to obtain personal information, or falsify charging information.
Conventionally, the device/system is protected from such illegal acts by physical means, for example, a substrate carrying a large scale integration (LSI) chip is covered by resin or the like in the device, or a casing of the device is fabricated in such a manner as to make disassembly difficult. Thus, the alteration of the device/system is made difficult.
According to another conventional technique, a digital signal processor (DSP) reads out boot software from a read only memory (ROM) inside the device to perform authentication based on a device identification code and a manufacturer identification code, and executes booting only when the authentication is successful (see for example, Japanese Patent Application Laid-Open No. 2003-108257).
According to still another conventional technique, secure booting is performed to prevent an execution of an illegally overwritten program code, and an execution of a program code other than authenticated program code is blocked. According to one known method, a security chip called Trusted Platform Module (TPM) is employed for the implementation of secure booting.
The physical solution as described above such as resin-coating or casing reinforcement, however, increases manufacturing cost and tends to be nullified by special processing technique.
On the other hand, technique such as secure booting needs a special hardware module like TPM. In addition, since TPM of each device has a peculiar encryption key which is different from each other, to update an execution program, a newly configured program must be distributed to each device so that the program can be authenticated by a peculiar encryption key of each device. Hence, maintenance cost becomes astronomical.
Still further, though capable of checking the authenticity of a predetermined program at the activation, the secure booting technique has difficulties in detecting the leakage of the program or the hardware alteration.